1. Field of the Invention
The present invention relates to a recording medium.
2. Description of the Related Art
A recording medium that includes an ink-receiving layer that contains inorganic particles has been used because it has good ink absorbency and allows an image having high color developability to be formed. Generally, the recording medium that includes an ink-receiving layer that contains inorganic particles is prepared by applying an ink-receiving layer coating liquid that contains the inorganic particles to a base material and subsequently drying the resulting coating film. However, there have been technical problems with the above-described method where the viscosity of the ink-receiving layer coating liquid may be disadvantageously increased while the coating liquid is prepared, or cracking may occur in the ink-receiving layer while the ink-receiving layer is drying.
In order to address the above-described technical problems that may occur during application of the ink-receiving layer coating liquid, hitherto, there have been proposed methods (e.g., Japanese Patent Laid-Open Nos. 2006-232586 and 2007-245713, hereinafter referred to as “PTL 1” and “PTL 2”, respectively) in which a specific material is used for preparing the ink-receiving layer coating liquid or the pH of the ink-receiving layer coating liquid is controlled to a specific value. In PTL 1, it is described that controlling the pH of a coating liquid that includes fumed silica reduces the viscosity of the coating liquid, which reduces occurrence of cracking in the ink-receiving layer. In PTL 2, it is described that use of a coating liquid that includes inorganic particles, a silane coupling agent, and at least one substance selected from the group consisting of a basic inorganic salt and ammonia and that has a pH of 5.0 or less reduces occurrence of cracking in the ink-receiving layer. In PTL 2, it is also described that the silane coupling agent is adsorbed onto the surfaces of the inorganic particles.
However, a recording medium that includes an ink-receiving layer that contains inorganic particles modified with a silane coupling agent as in PTL 2 is known in the related art. In Japanese Patent Laid-Open No. 2006-231786 (hereinafter, referred to as “PTL 3”), a recording medium that includes an ink-receiving layer that contains inorganic particles that are surface-modified with a silane coupling agent having a reactive substituent and inorganic particles that are surface-modified with another silane coupling agent having a functional group that reacts with the reactive substituent is described. In PTL 3, it is described that this recording medium has good ink absorbency and high surface strength and allows an image having high color developability to be formed. The silane coupling agents described in PTLs 2 and 3 do not include hydroxyl groups.